1. Field of the Invention
The present invention relates to a water discharge apparatus adapted to discharge aerated bubbly water.
2. Description of the Related Art
Known examples of water discharge apparatuses include one which discharges bubbly water by aerating water using a so-called ejector effect. When the water discharge apparatus is configured as a shower apparatus which distributes the water flowing into the apparatus to multiple nozzle holes and sprays water therefrom, in order to aerate the discharged water, the water flowing into the apparatus is aerated before being distributed among the nozzle holes.
An example of such a shower apparatus is proposed in National Publication of International Patent Application No. 2006-509629. The shower apparatus described in National Publication of International Patent Application No. 2006-509629 comprises a plurality of nozzle holes provided in a front face of a disk-shaped housing shell and is configured to discharge water flowing in through the center of a rear face of the housing shell by distributing the water to the plurality of nozzle holes. Furthermore, the shower apparatus produces bubbly water by aerating the water which has flowed into the housing shell and distributes the bubbly water to the plurality of nozzle holes formed so as to distribute the bubbly water over the entire front face of the disk-shaped housing shell. Therefore, a turbulence generation/expansion unit is placed in a traveling direction of the bubbly water, causing the bubbly water to change direction by colliding with the turbulence generation/expansion unit and thereby spread over the entire front face of the housing shell.
Another example of a shower apparatus is proposed in Japanese Patent No. 3747323. With the shower apparatus described in Japanese Patent No. 3747323, when a cock such as a hot and cold mixer tap is opened, water is supplied from a hose and passed through an orifice member. Then, the water is mixed with air sucked through an inner suction port open to a decompression chamber installed on a downstream side of the orifice member and maintained under reduced pressure at the given moment. The shower apparatus described in Japanese Patent No. 3747323 produces bubbly water in this way and discharges the bubbly water through a plurality of nozzle holes provided in a shower head. With the shower apparatus, the produced bubbly water proceeds to the nozzle holes by changing direction by hitting a threaded member in a partitioned pipe installed on the downstream side of the decompression chamber as well as inner walls of the shower head installed further downstream.
Furthermore, from the viewpoint of shower apparatus adapted to discharge bubbly water, a shower apparatus is proposed in Japanese Patent Laid-Open No. 2008-237601. The shower apparatus described in Japanese Patent Laid-Open No. 2008-237601 includes a fine-bubble generator equipped with a gas mixing unit for mixing gas in a water supply line through which shower water flows and adapted to break up the gas mixed in the shower water by the gas mixing unit into fine bubbles and put fine bubbles with bubble diameters of 0.1 to 1000 μm into the shower water discharged from a shower water discharge unit installed at an outlet of the water supply line. The gas mixing unit is provided with gas mixing rate control means adapted to control a mixing rate of the shower water and a gas flow control valve of the gas mixing rate control means is installed in a gas supply channel, where the gas flow control valve is a solenoid valve. The gas flow control valve has its opening controlled by being connected to a control unit adapted to control operation of the shower apparatus. That is, opening control of the gas flow control valve adjusts the channel diameter of the gas supply channel and thereby makes the flow rate of the gas flowing through the gas supply channel variable.
The shower apparatus described in Japanese Patent No. 3747323 is intended to achieve the sensation of water hitting the user intermittently as described in paragraph 0015 of Japanese Patent No. 3747323. The term “intermittently” means that finely divided water droplets of nonuniform sizes hit the user. It is considered that the term expresses a mixed sensation of intermittent strong and weak showers which can be experienced by the user if hit by large-size water droplets which produce a sensation of a strong shower and small-size water droplets which produce a sensation of a weak shower. According to concrete studies conducted by the present inventors, it is presumed that in the bubbly water just produced, water is mixed substantially uniformly with air. Then, the bubbles collide with each other as the produced bubbly water changes direction by hitting the threaded member and the inner walls of the shower head, and it is considered that bubble diameters are nonuniform when the bubbly water reaches the nozzle hoses. Consequently, when discharged from the nozzle holes, the bubbly water turns into water droplets of nonuniform sizes, which are considered to achieve the sensation described above when directed at the user.
On the other hand, National Publication of International Patent Application No. 2006-509629 does not give any description of properties of the bubbly water discharged from the shower apparatus described in National Publication of International Patent Application No. 2006-509629. However, it is presumed that the shower apparatus produces water droplets of nonuniform sizes by supplying and discharging bubbly water with nonuniform bubble diameters from the nozzle holes and directs the water droplets of nonuniform sizes at the user, as in the case of the shower apparatus described in Japanese Patent No. 3747323. This is because since in the shower apparatus described in National Publication of International Patent Application No. 2006-509629, the turbulence generation/expansion unit is placed in the traveling direction of the bubbly water, causing the bubbly water to change direction by colliding with the turbulence generation/expansion unit, it is considered that similar nonuniform bubble growth takes place in the shower apparatus described in Japanese Patent No. 3747323 and that resulting water droplets of nonuniform sizes are directed at the user. Since both the shower apparatus described in National Publication of International Patent Application No. 2006-509629 and shower apparatus described in Japanese Patent No. 3747323 throw water droplets of nonuniform sizes at the user using bubbly water containing nonuniform bubbles, they produce only a small difference between sensations of strong and weak showers, and consequently a sufficient stimulus sensation is not available.
On the other hand, in the shower apparatus described in Japanese Patent Laid-Open No. 2008-237601, the solenoid valve acting as the gas flow control valve of the gas mixing rate control means is installed in the gas supply channel. Although the gas mixing rate control means allows intentional control of the bubble content, a solenoid valve acting as the gas flow control valve becomes necessary. Thus, although the shower apparatus described in Japanese Patent Laid-Open No. 2008-237601 may be able to discharge bubbly water with a stimulus sensation, means of physically operating a structure such as the solenoid valve is required, resulting in a water discharge apparatus which runs counter to size and cost reductions.
Under these circumstances, the present thought of providing a water discharge apparatus which provides a voluminous feel even when discharging a small volume of water, causes an instantaneous flow rate of spray to change greatly, allows water to be discharged with a comfortable stimulus sensation, and lends itself to size and cost reductions, where the water discharge apparatus may be not only a shower apparatus, but also a sanitary cleansing apparatus which discharges water through a single orifice. In contrast, the conventional techniques, which achieve the sensation of nonuniformly-sized water droplets hitting the user as described above, do not provide spray of a shower with a comfortable stimulus sensation of the instantaneous flow rate of the spray varying greatly as well as with a voluminous feel. Besides, the conventional techniques are not able to provide spray of a shower with a comfortable stimulus sensation of the instantaneous flow rate of the spray varying greatly as well as with a voluminous feel while achieving size and cost reductions.